Over 100 of these, built from about the 8th to the 13th centuries, exist in Ireland, most of them now in ruins.
The lower part is constructed of solid masonry, with a high doorway accessible only by ladder, and with walls tapering inward to the top.
Of varied size, their height is from 60 to 132 feet, that at Kilcullen being the highest.
Having Christian embellishments and always built near a church, they were doubtless constructed by Christians for purposes of refuge.
On the side of Scotland remote from Ireland, strangely enough, there are three round towers of the Irish type, viz., Egilshay in Orkney, Abernethy, and Brechin; there is one in the Isle of Man, and several Norman examples in Norfolk, Suffolk, and Essex.
Lower and wider round towers existed in various European localities in pre-Christian times, e.g., the Nuraghi of Sardinia.
New Catholic Dictionary